When fruit flies see or smell their dead comrades, their own lives are cut short. Talk about putting a damper on your day!
Fruit flies stress after seeing other dead fruit flies
If you’re a fruit fly, seeing one of your fallen is not just unsettling. It’s downright harmful to your health. Despite their diminutive size, experience stress and negative health effects when they witness the remains of their kin.
Neuroscientists have found that when fruit flies (Drosophila melanogaster) see their deceased fellow flies, specific brain cells are triggered.
And these aren’t just any brain cells. They are neurons that respond to visual stimuli, known as visual projection neurons (VPNs). These cells relay information from the flies’ eyes to their brains, helping them interpret and react to what they see.
What’s going on in a fruit fly’s brain?
But let’s add a pinch of intrigue to the mix. These neuroscientists didn’t stop at merely identifying the type of neurons involved. They zeroed in on the specific group of neurons that reacts to the sight of dead flies. The neurons in question are part of a cluster known as the “globus pallidus.” This is an area associated with movement and learning.
These scientists have discovered the precise neighborhood in the fruit fly’s brain where the “dead fly sighting stress response” takes place.
So, what happens when these neurons fire? In short, they trigger a series of stress responses that have a tangible impact on the fruit flies’ health and lifespan. As the sight of a dead fellow fly becomes ingrained in the fly’s brain, it alters the expression of stress-related genes, tipping the physiological balance and leading to a shorter lifespan.
This discovery has raised intriguing questions about the evolution of empathy and social responses in insects. While fruit flies may not experience empathy in the way humans do, their stress response to seeing dead comrades suggests a level of social awareness. This raises the question: why would such a response evolve? One possibility is that the sight of death serves as a warning signal, indicating the presence of potential threats or diseases, thus prompting the fly to modify its behavior.
However, this remarkable finding does more than just throw light on fruit flies’ stress responses. It could also contribute to our understanding of how human brains process stress and trauma. Humans, like fruit flies, have neurons that respond to visual stimuli. Therefore, these findings could lead to a better understanding of how our brains respond to stressful visual experiences, and potentially inform treatments for stress-related disorders.
Source: “Seeing dead fruit flies is bad for the health of fruit flies – and neuroscientists have identified the exact brain cells responsible” — The Conversation